Effect of the index of consciousness 2 on intraoperative opioid dosage in ovarian cancer patients receiving neoadjuvant chemotherapy: a study protocol for a randomised controlled trial.

INTRODUCTION: For ovarian cancer patients undergoing preoperative Neoadjuvant Chemotherapy (NACT), the toxicity of chemotherapeutic agents may cause hepatic and renal function impairment, altered sensitivity of the central nervous system or abnormal pain perception thresholds. These changes can further affect the metabolism and efficacy of intraoperative anaesthetics. However, the optimal intraoperative opioid dosage regimen for this specific patient population remains unclear. Currently, nociceptive stimulation monitoring technology has achieved certain progress in guiding intraoperative opioid administration. Among this technology, the index of consciousness 2 (IOC2), as a representative monitoring indicator in this field, provides important references for optimising opioid dosage regimens. This trial will investigate the opioid requirements and patient outcomes in the anaesthetic management of ovarian cancer patients undergoing preoperative NACT guided by IOC2. METHODS AND ANALYSIS: This prospective, single-blind, single-centre randomised controlled trial will randomly recruit 90 patients undergoing open ovarian cancer cytoreductive surgery under general anaesthesia, with equal numbers assigned to the control and experimental groups. The experimental group will adjust the remifentanil plasma target concentration based on the IOC2 value, while the control group will adjust according to the patients' mean arterial pressure. The primary outcome will be intraoperative opioid use (calculated in morphine equivalents per hour). Secondary outcomes include the average intraoperative propofol dose, post-anaesthesia care unit (PACU)-related metrics (including extubation time, time to spontaneous eye opening and morphine consumption in PACU), pain levels at 4, 24 and 48 hours postoperatively, as well as the use of analgesics and antiemetics. Postoperative recovery quality will also be assessed, including time to first flatus, time to ambulation, length of hospital stay and the 24-hour Quality of Recovery-15 (QoR-15) score. ETHICS AND DISSEMINATION: This study involves human participants and was approved by the Ethics Committee of the Jiangsu Cancer Hospital (ethics no: XJS-2024-017). Patients gave informed consent to participate in the study before taking part. The study results will be published in peer-reviewed journals and presented at relevant academic conferences. TRIAL REGISTRATION NUMBER: ChiCTR2400091897.